CybersecurityUntraceable communication -- guaranteed

Anonymity networks, which sit on top of the public Internet, are designed to conceal people’s Web-browsing habits from prying eyes. The most popular of these, Tor, has been around for more than a decade and is used by millions of people every day. Recent research, however, has shown that adversaries can infer a great deal about the sources of supposedly anonymous communications by monitoring data traffic though just a few well-chosen nodes in an anonymity network. Researchers have developed a new, untraceable text-messaging system designed to thwart even the most powerful of adversaries.

Anonymity networks, which sit on top of the public Internet, are designed to conceal people’s Web-browsing habits from prying eyes. The most popular of these, Tor, has been around for more than a decade and is used by millions of people every day.

Recent research, however, has shown that adversaries can infer a great deal about the sources of supposedly anonymous communications by monitoring data traffic though just a few well-chosen nodes in an anonymity network. At the Association for Computing Machinery Symposium on Operating Systems Principles in October, a team of MIT researchers presented a new, untraceable text-messaging system designed to thwart even the most powerful of adversaries.

The system provides a strong mathematical guarantee of user anonymity, while, according to experimental results, permitting the exchange of text messages once a minute or so.

“Tor operates under the assumption that there’s not a global adversary that’s paying attention to every single link in the world,” says Nickolai Zeldovich, an associate professor of computer science and engineering, whose group developed the new system. “Maybe these days this is not as good of an assumption. Tor also assumes that no single bad guy controls a large number of nodes in their system. We’re also now thinking, maybe there are people who can compromise half of your servers.”

Because the system confuses adversaries by drowning telltale traffic patterns in spurious information, or “noise,” its creators have dubbed it “Vuvuzela,” after the noisemakers favored by soccer fans at the 2010 World Cup in South Africa.

Covering your tracksVuvuzela is a dead-drop system, in which one user leaves a message for another at a predefined location — in this case, a memory address on an Internet-connected server — and the other user retrieves it. But it adds several layers of obfuscation to cover the users’ trails.

To illustrate how the system works, Lazar describes a simplified scenario in which it has only three users, named, by cryptographic convention, Alice, Bob, and Charlie. Alice and Bob wish to exchange text messages,